EFFECTS OF AMPHETAMINE, CHLORPROMAZINE, PENTOBARBITAL, AND ETHANOL ON OPERANT RESPONSE DURATION

¹ Department of Pharmacology and Experimental Therapeutics and Department of Medicine (Division of Clinical Pharmacology), The Johns Hopkins University School of Medicine, Baltimore, Maryland

Dogs were trained to press against a response button with their noses. Whenever a dog accumulated 1 minute of nose-pressing, a food reinforcement was delivered. No restriction was placed on the number of individual responses needed to accumulate the 1-minute total. Amphetamine, pentobarbital, and ethanol all produced increases in the number of responses per reinforcement as dose was increased. Chlorpromazine had no effect up to a dose that caused the dogs to sleep. Combinations of amphetamine and ethanol, or amphetamine and pentobarbital produced substantial increases in the effects observed with the individual doses.